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Nanoscale pyrogenic oxides

Inactive Publication Date: 2007-08-02
EVONIK DEGUSSA GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Benefits of technology

[0010] The object thus arises of producing nanoscale, pyrogenic oxides having a low chloride con

Problems solved by technology

These products produced in this manner have the disadvantage that, especially in the case of basic oxides, they have elevated chloride contents because they may be deacidified only very incompletely.
Raising the temperature to higher levels during deacidification is not possible because this would amount to excessive exposure to elevated temperatures and result in an unwanted loss of surface area.
On the other hand, it is desirable that the chloride is removed as completely as possible, as this residual chloride content gives rise to corrosion problems when the oxides are used.
The known process for the production of pyrogenic oxides furthermore has the disadvantage that, for example in the case of aluminium chloride or zirconium tetrachloride, very high vaporisation temperatures must be used in order to be able to convert the starting materials into the gas phase.
These vaporisation conditions place extremely stringent and thus very costly demands upon the materials of the production plant.

Method used

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  • Nanoscale pyrogenic oxides
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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0035] 1 l / h of Zr(O-n-C3H7)4 as a 74% solution in n-propanol is atomised into the tubular reactor under nitrogen pressure using a nozzle. An oxyhydrogen flame of hydrogen and air burns in the reactor. The temperature 0.5 m below the flame is 800 to 1000° C. The ZrO2 is separated in filters. Phase analysis reveals the principal constituent to be monoclinic ZrO2 having a very low Cl content. As Table 1 shows, the BET surface area may be influenced by varying the nozzle diameter and the quantity of atomising air.

TABLE 1Test 1Test 2Test 3Delivery rate, l / h111Temperature, ° C.800-1000800-1000800-1000V H2, m3 / h1.51.51.5V atomising gas, bar2714V air, m3 / h13.51620Nozzle diameter, mm10.80.8BET surface area, m2 / g183279ColourwhitewhitewhiteCl, %0.010.010.01Tamped density, g / l154154Phase analysisMonoclinic (principal constituent)Tetragonal and cubic (secondary constituent)Drying loss, %0.5Ignition loss, %0.0pH value4.6ZrO2, %97.5597.60HfO2, %2.142.14

example 2

[0036] Aluminium nitrate as a 3% (test 1) or 7.5% (test 2) aqueous solution, or liquid aluminium tri-sec.-butylate (tests 3 and 4) are atomised into the tubular reactor with compressed air and a nozzle (diameter 0.8 mm) or in the case of test 2 with an atomiser (diameter 1.1 mm). An oxyhydrogen flame of hydrogen, air and / or oxygen mixture burns in the reactor. The temperature 0.5 m below the flame is 250° C. to 1250° C. The aluminium oxide is separated in filters. The results are shown in Table 2.

TABLE 2Test 1Test 2Test 3Test 4Delivery rate, ml / h320230100120Temperature, ° C.650-250700-1200560-9001150-1300V H2, m3 / h0.61.50.91.6V atomising gas,1.40Two-fluid0carrier gas, barnozzle,0.8 mmdiameter2.3V air, m3 / h1.02.22.82.1BET, m2 / g3.1920516D 50 (Cilas)1.5224.73.474.52Phase100%70% alpha16% delta100% alphaamorphous30% theta84% gammaTEM, μmCompactCrystallites0.005-0.0010spheresup to 4 m0.2-2Cl content, %0.018

example 3

[0037] Titanium bis(ammoniumlactato)dihydroxide ((CH3CH(O—) CO2NH4)2Ti(OH)2) as a 50% aqueous solution is atomised into the tubular reactor using compressed air and a nebuliser. An oxyhydrogen flame of hydrogen, air and / or oxygen mixture burns in the reactor. The temperature 0.5 m below the flame is 740° C. to 1 150° C. The titanium oxide is separated in filters. The data are shown in Table 3.

TABLE 3Delivery rate, ml / h200Temperature, ° C.740-1150V H2, m3 / h1.8V nebuliser carrier gas, bar1.8V air, m3 / h1.3BET, m2 / g3.1D 50 (Cilas)0.92Phase100% rutile

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Abstract

Nanoscale, pyrogenically produced oxides and / or mixed oxides having a BET surface area of between 1 m2 / g and 600 m2 / g and a chloride content of less than 0.05 wt. % are produced by converting organometallic and / or organometalloid substances into the oxides at temperatures of above 200° C. The oxides may be used as a polishing agent in the electronics industry (CMP).

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This is a continuing application of U.S. patent application Ser. No. 09 / 821,797, filed Mar. 30, 2001, which claims priority to U.S. Provisional Application Ser. No. 60 / 194,367, filed Apr. 4, 2000, and European Patent Application No. 00 107 237.0, filed Apr. 3, 2000, all of which are herein incorporated in their entirety by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] This invention relates to nanoscale, pyrogenically produced oxides, to a process for the production thereof and to the use thereof. [0004] 2. Description of Related Art [0005] It is known to produce pyrogenic oxides by flame hydrolysis of vaporisable metal chlorides or metalloid chlorides (Ullmanns Enzyklopädie der technischen Chemie, 4th edition, volume 21, page 44 (1982)). [0006] These products produced in this manner have the disadvantage that, especially in the case of basic oxides, they have elevated chloride contents because they may b...

Claims

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Application Information

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IPC IPC(8): C04B14/00C01B13/14C01B13/34C01F7/304C01F7/306C01G23/07C01G25/02
CPCB82Y30/00Y10T428/2982C01B13/34C01F7/304C01F7/306C01G1/02C01G23/07C01G25/02C01P2002/02C01P2002/76C01P2004/32C01P2004/61C01P2004/62C01P2004/64C01P2006/12C01P2006/80C09K3/1409C01B13/20
Inventor GUTSCH, ANDREASHENNIG, THOMASKATUSIC, STIPANKRAMER, MICHAELMICHAEL, GUNTHERVARGA, GEOFFREY J.
Owner EVONIK DEGUSSA GMBH
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